CN109038515A - A kind of Hybrid HVDC route traveling-wave protection method and system based on Dual Tree Complex Wavelet variation - Google Patents
A kind of Hybrid HVDC route traveling-wave protection method and system based on Dual Tree Complex Wavelet variation Download PDFInfo
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- CN109038515A CN109038515A CN201810747106.6A CN201810747106A CN109038515A CN 109038515 A CN109038515 A CN 109038515A CN 201810747106 A CN201810747106 A CN 201810747106A CN 109038515 A CN109038515 A CN 109038515A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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Abstract
The invention discloses a kind of Hybrid HVDC route traveling-wave protection methods and system based on Dual Tree Complex Wavelet variation, comprising: calculates voltage difference modulus and voltage common mode amount according to the DC voltage of the positive and negative anodes of acquisition;The dual tree complex wavelet transform of voltage difference modulus is calculated using dual tree complex wavelet transform, and judges whether protection starts according to high sensitivity starting judgment basis;When determining protection starting, fault type is judged using the breakdown judge foundation of Hybrid HVDC route according to voltage common mode amount, the dual tree complex wavelet transform of voltage difference modulus and corresponding failure extreme value and carries out corresponding protection act.The present invention can rapidly distinguish the failure of Hybrid HVDC route, and it can reliably carry out failure and select pole, greatly reduce the translation sensibility in common real valued wavelet transform, the accuracy of accident analysis in long distance transmission line can be significantly improved, realizes the quick discrimination of Hybrid HVDC line fault.
Description
Technical field
The present invention relates to the technical field of relay protection of electrical technology, and are based on antithesis tree more particularly, to one kind
The Hybrid HVDC route traveling-wave protection method and system of Phase information variation.
Background technique
Line commutation converter type HVDC transmission system (Li ne Commutated based on thyristor technology
Converter, LCC-HVDC) be widely used to the occasions such as long-distance and large-capacity power transmission, Asynchronous Interconnection, but it there are inversions
The problem of side commutation failure.HVDC transmission system (Voltage Source based on voltage source converter
Converter, VSC-HVDC) with its independent control active power, reactive power, it can operate at passive system, not by commutation
The advantages such as influence of failure are developed rapidly, but it haves the shortcomings that involve great expense, running wastage is big.Mixed DC is defeated
Electric system (LCC-VSC) is a kind of novel direct current transportation topological structure, it combines the advantage of both LCC and VSC, in receiving end
Using the operation characteristic that can improve receiving end AC system when VSC, therefore it is suitable for the access extra-high straightening of multi-infeed HVDC power grid
The construction of engineering and the transformation of LCC-HVDC receiving end converter station are flowed, there is good future in engineering applications.
Mixed DC route protection is the critical issue of mixed DC development, and technical difficult points are fast and reliablely
Identify fault section.Due to Hybrid HVDC line fault transient characteristic and primary equipment inherently constitute it is straight with single routine
Stream transmission of electricity, flexible DC transmission it is variant, therefore, conventional AC system protection, customary DC transmission system protection and it is soft
Property DC transmission system protection can not directly apply to Hybrid HVDC system.In terms of algorithm, traditional discrete wavelet
Input signal is decomposed into high and low frequency component first by transformation, is extracted using two and is obtained coefficient of wavelet decomposition, but discrete
Two extraction processes of wavelet transformation can cause biggish aliasing, bring distortion, seriously affect wavelet coefficient characterization original signal feature
Ability.
Summary of the invention
The present invention propose it is a kind of based on Dual Tree Complex Wavelet variation Hybrid HVDC route traveling-wave protection method and be
System, to solve the problems, such as how quickly to determine the failure of Hybrid HVDC route.
To solve the above-mentioned problems, according to an aspect of the invention, there is provided a kind of changed based on Dual Tree Complex Wavelet
Hybrid HVDC route traveling-wave protection method, which is characterized in that the described method includes:
Voltage difference modulus and voltage common mode amount are calculated according to the DC voltage of the positive and negative anodes of acquisition;
The dual tree complex wavelet transform of voltage difference modulus is calculated using dual tree complex wavelet transform, and is opened according to high sensitivity
Dynamic judgment basis judges whether protection starts;
When determining protection starting, according to voltage common mode amount, the dual tree complex wavelet transform of voltage difference modulus and corresponding
Failure extreme value using the breakdown judge of Hybrid HVDC route according to judging fault type and carry out corresponding protection act,
In, the breakdown judge foundation of the Hybrid HVDC route includes: bipolar error protection judgment basis, monopole metallicity failure
Protection judgment basis, monopole protect judgment basis and failure to select pole judgment basis through transition Resistance Fault.
Preferably, wherein calculating voltage difference modulus and voltage common mode amount using following formula:
F (x)=0.5x (U1-U2),
f1(x)=0.5x (U1+U2),
Wherein, f (x) is voltage difference modulus;f1It (x) is voltage common mode amount;U1And U2The direct current of the positive and negative anodes respectively acquired
Voltage.
Preferably, wherein it is described using dual tree complex wavelet transform calculate voltage difference modulus dual tree complex wavelet transform,
And judge whether protection starts according to high sensitivity starting judgment basis, comprising:
The dual tree complex wavelet transform W of differential mode amount is calculated using dual numbers complex wavelet transformSF (x), and according to high sensitivity
Starting judgment basis judges WSWhether f (x) > Δ 3 meets, if WSF (x) > Δ 3, it is determined that protection starting, and it is total to calculate voltage
The three cubed integrated value ∫ U of moduluscom 3;Conversely, determining that protection does not start;Wherein, S is scaling function;Δ 3 is that third presets threshold
Value is positive value.
Preferably, wherein
The bipolar error protection judgment basis are as follows:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route;
The monopole metallicity error protection judgment basis are as follows:
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure;
The monopole protects judgment basis through transition Resistance Fault are as follows:
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault;
The failure selects pole judgment basis are as follows:
If ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault;
Wherein, f (x) is voltage difference modulus;WSF (x) is the dual tree complex wavelet transform of f (x);S is scaling function, x01For
The modulus maximum point of dual tree complex wavelet transform when line end bipolar failure;WSf(x01) when being the bipolar failure of line end pair
The modulus maximum of even tree complex wavelet transformation, k1For the coefficient of ratio;x02Antithesis tree when for line end monopole metallic earthing failure
The modulus maximum point of complex wavelet transform;WSf(x02) be line end monopole failure when dual tree complex wavelet transform modulus maximum;
k2For the coefficient of ratio;x03Modulus maximum point for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;WSf
(x03) it is modulus maximum of the line end monopole through dual tree complex wavelet transform when transition Resistance Fault;k3For the coefficient of ratio;f1
It (x) is voltage common mode amount, it is positive value that Δ 1, which is the first preset threshold,;Δ 2 is the second preset threshold, is negative value.
Preferably, wherein it is described when determining protection starting, it is multiple small according to the antithesis tree of voltage common mode amount, voltage difference modulus
Wave conversion and corresponding failure extreme value judge fault type using the breakdown judge foundation of Hybrid HVDC route and carry out phase
The protection act answered, comprising:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route, and positive and negative polar curve
Road traveling-wave protection quick acting;
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure, and select using failure
Pole judgment basis judges the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode traveling-wave protection is quick
Movement;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting;
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault, and using simultaneously
Pole judgment basis is selected to judge the polarity of failure using failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode row
Wave protects quick acting;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting.
According to another aspect of the present invention, a kind of Hybrid HVDC line based on Dual Tree Complex Wavelet variation is provided
Road traveling-wave protection system, which is characterized in that the system comprises:
Computing unit, the DC voltage for the positive and negative anodes according to acquisition calculate voltage difference modulus and voltage common mode amount;
Judging unit, for calculating the dual tree complex wavelet transform of voltage difference modulus using dual tree complex wavelet transform, and
Judge whether protection starts according to high sensitivity starting judgment basis;
Protection location is used for when determining protection starting, according to voltage common mode amount, the Dual Tree Complex Wavelet of voltage difference modulus
Transformation and corresponding failure extreme value judge fault type using the breakdown judge foundation of Hybrid HVDC route and carry out corresponding
Protection act, wherein the breakdown judge of the Hybrid HVDC route according to include: bipolar error protection judgment basis,
Monopole metallicity error protection judgment basis, monopole protect judgment basis and failure to select pole judgment basis through transition Resistance Fault.
Preferably, wherein in the computing unit, voltage difference modulus and voltage common mode amount are calculated using following formula:
F (x)=0.5x (U1-U2),
f1(x)=0.5x (U1+U2),
Wherein, f (x) is voltage difference modulus;f1It (x) is voltage common mode amount;U1And U2The direct current of the positive and negative anodes respectively acquired
Voltage.
Preferably, wherein in the judging unit, the antithesis tree of voltage difference modulus is calculated using dual tree complex wavelet transform
Complex wavelet transform, and judge whether protection starts according to high sensitivity starting judgment basis, comprising:
The dual tree complex wavelet transform W of differential mode amount is calculated using dual numbers complex wavelet transformSF (x), and according to high sensitivity
Starting judgment basis judges WSWhether f (x) > Δ 3 meets, if WSF (x) > Δ 3, it is determined that protection starting, and it is total to calculate voltage
The three cubed integrated value ∫ U of moduluscom 3;Conversely, determining that protection does not start;Wherein, S is scaling function;Δ 3 is that third presets threshold
Value is positive value.
Preferably, wherein
The bipolar error protection judgment basis are as follows:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route;
The monopole metallicity error protection judgment basis are as follows:
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure;
The monopole protects judgment basis through transition Resistance Fault are as follows:
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault;
The failure selects pole judgment basis are as follows:
If ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault;
Wherein, f (x) is voltage difference modulus;WSF (x) is the dual tree complex wavelet transform of f (x);S is scaling function, x01For
The modulus maximum point of dual tree complex wavelet transform when line end bipolar failure;WSf(x01) when being the bipolar failure of line end pair
The modulus maximum of even tree complex wavelet transformation, k1For the coefficient of ratio;x02Antithesis tree when for line end monopole metallic earthing failure
The modulus maximum point of complex wavelet transform;WSf(x02) be line end monopole failure when dual tree complex wavelet transform modulus maximum;
k2For the coefficient of ratio;x03Modulus maximum point for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;WSf
(x03) it is modulus maximum of the line end monopole through dual tree complex wavelet transform when transition Resistance Fault;k3For the coefficient of ratio;f1
It (x) is voltage common mode amount, it is positive value that Δ 1, which is the first preset threshold,;Δ 2 is the second preset threshold, is negative value.
Preferably, wherein in the protection location, when determining protection starting, according to voltage common mode amount, voltage difference modulus
Dual tree complex wavelet transform and corresponding failure extreme value using the breakdown judge of Hybrid HVDC route according to judging failure
Type simultaneously carries out corresponding protection act, comprising:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route, and positive and negative polar curve
Road traveling-wave protection quick acting;
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure, and select using failure
Pole judgment basis judges the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode traveling-wave protection is quick
Movement;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting;
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault, and using simultaneously
Pole judgment basis is selected to judge the polarity of failure using failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode row
Wave protects quick acting;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting.
The present invention provides it is a kind of based on Dual Tree Complex Wavelet variation Hybrid HVDC route traveling-wave protection method and
System, voltage difference modulus medium-high frequency transient state component carries out traveling-wave protection, the party after extracting decoupling using dual tree complex wavelet transform
Method is transmitted electricity and the traveling-wave protection on flexible DC transmission route compared at present applied to customary DC, and mixing can be rapidly distinguished
The failure of DC power transmission line, and can reliably carry out failure and select pole, greatly reduce the translation in common real valued wavelet transform
Sensibility realizes the accurate extraction of sampled data high fdrequency component in short-data windows, solves the existing remote sensitivity of protection not
The problem of foot can significantly improve the accuracy of accident analysis in long distance transmission line, realize the event of Hybrid HVDC route
The quick discrimination of barrier.
Detailed description of the invention
By reference to the following drawings, exemplary embodiments of the present invention can be more fully understood by:
Fig. 1 is to be protected according to the Hybrid HVDC route traveling wave based on Dual Tree Complex Wavelet variation of embodiment of the present invention
The flow chart of maintaining method 100;
Fig. 2 is to be protected according to the Hybrid HVDC route traveling wave based on Dual Tree Complex Wavelet variation of embodiment of the present invention
The structural schematic diagram of protecting system 200.
Specific embodiment
Exemplary embodiments of the present invention are introduced referring now to the drawings, however, the present invention can use many different shapes
Formula is implemented, and is not limited to the embodiment described herein, and to provide these embodiments be at large and fully disclose
The present invention, and the scope of the present invention is sufficiently conveyed to person of ordinary skill in the field.Show for what is be illustrated in the accompanying drawings
Term in example property embodiment is not limitation of the invention.In the accompanying drawings, identical cells/elements use identical attached
Icon note.
Unless otherwise indicated, term (including scientific and technical terminology) used herein has person of ordinary skill in the field
It is common to understand meaning.Further it will be understood that with the term that usually used dictionary limits, should be understood as and its
The context of related fields has consistent meaning, and is not construed as Utopian or too formal meaning.
Fig. 1 is to be protected according to the Hybrid HVDC route traveling wave based on Dual Tree Complex Wavelet variation of embodiment of the present invention
The flow chart of maintaining method 100.As shown in Figure 1, the mixed DC based on Dual Tree Complex Wavelet variation of embodiment of the present invention is defeated
Electric line traveling-wave protection method, voltage difference modulus medium-high frequency transient state component carries out after extracting decoupling using dual tree complex wavelet transform
Traveling-wave protection, this method are transmitted electricity and the traveling-wave protection on flexible DC transmission route compared at present applied to customary DC, can
The failure of Hybrid HVDC route is rapidly distinguished, and can reliably carry out failure and select pole, it is small greatly to reduce common reality
Translation sensibility in wave conversion realizes the accurate extraction of sampled data high fdrequency component in short-data windows, solves existing protection
Remote under-sensitive problem, can significantly improve the accuracy of accident analysis in long distance transmission line, realize mixing
The quick discrimination of direct current transmission line fault.The mixing based on Dual Tree Complex Wavelet variation that embodiments of the present invention provide is straight
Transmission line travelling wave guard method 100 is flowed since step 101 place, in step 101 according to the DC voltage of the positive and negative anodes of acquisition
Calculate voltage difference modulus and voltage common mode amount.
Preferably, wherein calculating voltage difference modulus and voltage common mode amount using following formula:
F (x)=0.5x (U1-U2),
f1(x)=0.5x (U1+U2),
Wherein, f (x) is voltage difference modulus;f1It (x) is voltage common mode amount;U1And U2The direct current of the positive and negative anodes respectively acquired
Voltage.
Preferably, the dual tree complex wavelet transform of voltage difference modulus is calculated using dual tree complex wavelet transform in step 102,
And judge whether protection starts according to high sensitivity starting judgment basis.
Preferably, wherein it is described using dual tree complex wavelet transform calculate voltage difference modulus dual tree complex wavelet transform,
And judge whether protection starts according to high sensitivity starting judgment basis, comprising:
The dual tree complex wavelet transform W of differential mode amount is calculated using dual numbers complex wavelet transformSF (x), and according to high sensitivity
Starting judgment basis judges WSWhether f (x) > Δ 3 meets, if WSF (x) > Δ 3, it is determined that protection starting, and it is total to calculate voltage
The three cubed integrated value ∫ U of moduluscom 3;Conversely, determining that protection does not start;Wherein, S is scaling function;Δ 3 is that third presets threshold
Value is positive value.
Preferably, multiple according to the antithesis tree of voltage common mode amount, voltage difference modulus in step 103 when determining protection starting
Wavelet transformation and corresponding failure extreme value judge fault type using the breakdown judge foundation of Hybrid HVDC route and carry out
Corresponding protection act, wherein the breakdown judge of the Hybrid HVDC route according to include: bipolar error protection judge according to
According to, monopole metallicity error protection judgment basis, monopole through transition Resistance Fault protect judgment basis and failure select pole judge according to
According to.
Preferably, wherein
The bipolar error protection judgment basis are as follows:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route;
The monopole metallicity error protection judgment basis are as follows:
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure;
The monopole protects judgment basis through transition Resistance Fault are as follows:
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault;
The failure selects pole judgment basis are as follows:
If ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault;
Wherein, f (x) is voltage difference modulus;WSF (x) is the dual tree complex wavelet transform of f (x);S is scaling function, x01For
The modulus maximum point of dual tree complex wavelet transform when line end bipolar failure;WSf(x01) when being the bipolar failure of line end pair
The modulus maximum of even tree complex wavelet transformation, k1For the coefficient of ratio;x02Antithesis tree when for line end monopole metallic earthing failure
The modulus maximum point of complex wavelet transform;WSf(x02) be line end monopole failure when dual tree complex wavelet transform modulus maximum;
k2For the coefficient of ratio;x03Modulus maximum point for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;WSf
(x03) it is modulus maximum of the line end monopole through dual tree complex wavelet transform when transition Resistance Fault;k3For the coefficient of ratio;f1
It (x) is voltage common mode amount, it is positive value that Δ 1, which is the first preset threshold,;Δ 2 is the second preset threshold, is negative value.
Preferably, wherein it is described when determining protection starting, it is multiple small according to the antithesis tree of voltage common mode amount, voltage difference modulus
Wave conversion and corresponding failure extreme value judge fault type using the breakdown judge foundation of Hybrid HVDC route and carry out phase
The protection act answered, comprising:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route, and positive and negative polar curve
Road traveling-wave protection quick acting;
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure, and select using failure
Pole judgment basis judges the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode traveling-wave protection is quick
Movement;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting;
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault, and using simultaneously
Pole judgment basis is selected to judge the polarity of failure using failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode row
Wave protects quick acting;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting.
Under normal circumstances, WSF (x) < Δ 3, high sensitivity starting judgment basis do not start, Hybrid HVDC route
Traveling-wave protection is reliably failure to actuate.
When the bipolar troubles inside the sample space of Hybrid HVDC route, WSF (x) > k1WSf(x01), Hybrid HVDC route row
Wave protects quick acting.
When metallicity failure in Hybrid HVDC line monopole area, k2WSf(x02) < WSF (x) < k1WSf(x01), warp
It crosses failure and selects pole judgment basis, Hybrid HVDC route traveling-wave protection quick acting.
When in Hybrid HVDC line monopole area through transition Resistance Fault, k3WSf(x03) < WSF (x) < k2WSf
(x02), pole judgment basis, Hybrid HVDC route traveling-wave protection quick acting are selected by failure.
When Hybrid HVDC route external area error, WSF (x) < k3WSf(x03), Hybrid HVDC route traveling wave is protected
Shield is reliably failure to actuate.
In embodiments of the present invention, the Hybrid HVDC route traveling-wave protection side based on dual tree complex wavelet transform
Method, the specific steps are as follows:
Step1 acquires positive and negative anodes DC voltage U1And U2。
Step2 calculates voltage difference modulus Udif=0.5 × (U1-U2) and Ucom=0.5 × (U1+U2)。
Ste3 calculates differential mode amount W using dual numbers complex wavelet transformSUdif, compare WSUdifWith 3 size of Δ, if WSF (x) >
Δ 3 then protects starting, starts simultaneously at and calculates ∫ Ucom 3
Step4 compares WSUdifWith k1WSf(x01) size, if WSUdif> k1WSf(x01), then it is judged as Hybrid HVDC
Bipolar line failure, positive and negative anodes circuit traveling-wave protection quick acting.
If k2WSf(x02) < WSUdif< k1WSf(x01) meet ∫ U simultaneouslycom 3> Δ 1 is then judged as that Hybrid HVDC is negative
Polar curve road metallicity failure, anode circuit traveling-wave protection quick acting;If k2WSf(x02) < WSUdif< k1WSf(x01) full simultaneously
Sufficient ∫ Ucom 3< Δ 2 is then judged as Hybrid HVDC anode route metallicity failure, positive route traveling-wave protection quick acting.
If k3WSf(x03) < WSUdif< k2WSf(x02) meet ∫ U simultaneouslycom 3> Δ 1 is then judged as that Hybrid HVDC is negative
Polar curve road is through transition Resistance Fault, anode circuit traveling-wave protection quick acting;If k2WSf(x02) < WSUdif< k1WSf(x01) same
When meet ∫ Ucom 3< Δ 2 is then judged as Hybrid HVDC anode route by crossing Resistance Fault, positive route traveling-wave protection
Quick acting.
Fig. 2 is to be protected according to the Hybrid HVDC route traveling wave based on Dual Tree Complex Wavelet variation of embodiment of the present invention
The structural schematic diagram of protecting system 200.As shown in Fig. 2, embodiments of the present invention provide based on Dual Tree Complex Wavelet variation
Hybrid HVDC route traveling-wave protection system 200, comprising: computing unit 201, judging unit 202 and protection location 203.It is excellent
Selection of land, the computing unit 201, the DC voltage for the positive and negative anodes according to acquisition calculate voltage difference modulus and voltage common mode
Amount.
Preferably, wherein in the computing unit 201, voltage difference modulus and voltage common mode amount are calculated using following formula:
F (x)=0.5x (U1-U2),
f1(x)=0.5x (U1+U2),
Wherein, f (x) is voltage difference modulus;f1It (x) is voltage common mode amount;U1And U2The direct current of the positive and negative anodes respectively acquired
Voltage.
Preferably, the judging unit 202, for calculating the antithesis tree of voltage difference modulus using dual tree complex wavelet transform
Complex wavelet transform, and judge whether protection starts according to high sensitivity starting judgment basis.
Preferably, wherein in the judging unit 202, the antithesis of voltage difference modulus is calculated using dual tree complex wavelet transform
Tree complex wavelet transformation, and judge whether protection starts according to high sensitivity starting judgment basis, comprising:
The dual tree complex wavelet transform W of differential mode amount is calculated using dual numbers complex wavelet transformSF (x), and according to high sensitivity
Starting judgment basis judges WSWhether f (x) > Δ 3 meets, if WSF (x) > Δ 3, it is determined that protection starting, and it is total to calculate voltage
The three cubed integrated value ∫ U of moduluscom 3;Conversely, determining that protection does not start;Wherein, S is scaling function;Δ 3 is that third presets threshold
Value is positive value.
Preferably, the protection location 203 is used for when determining protection starting, according to voltage common mode amount, voltage difference modulus
Dual tree complex wavelet transform and corresponding failure extreme value using the breakdown judge of Hybrid HVDC route according to judging failure
Type simultaneously carries out corresponding protection act, wherein the breakdown judge foundation of the Hybrid HVDC route includes: bipolar failure
Judgment basis, monopole metallicity error protection judgment basis, monopole is protected to protect judgment basis and failure through transition Resistance Fault
Select pole judgment basis.
Preferably, wherein the bipolar error protection judgment basis are as follows: if WSF (x) > k1WSf(x01) set up, then it is judged as
The bipolar failure of Hybrid HVDC route.The monopole metallicity error protection judgment basis are as follows: if k2WSf(x02) < WSf(x)
< k1WSf(x01) set up, then it is judged as monopole metallicity failure.The monopole protects judgment basis through transition Resistance Fault are as follows:
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault.The failure selects pole to judge
Foundation are as follows: if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive event
Barrier.Wherein, f (x) is voltage difference modulus;WSF (x) is the dual tree complex wavelet transform of f (x);S is scaling function, x01For route
The modulus maximum point of dual tree complex wavelet transform when the bipolar failure in end;WSf(x01) antithesis tree when being line end bipolar failure
The modulus maximum of complex wavelet transform, k1For the coefficient of ratio;x02Antithesis tree is multiple small when for line end monopole metallic earthing failure
The modulus maximum point of wave conversion;WSf(x02) be line end monopole failure when dual tree complex wavelet transform modulus maximum;k2For
The coefficient of ratio;x03Modulus maximum point for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;WSf(x03)
Modulus maximum for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;k3For the coefficient of ratio;f1(x) it is
Voltage common mode amount, Δ 1 are the first preset threshold, are positive value;Δ 2 is the second preset threshold, is negative value.
Preferably, wherein in the protection location, when determining protection starting, according to voltage common mode amount, voltage difference modulus
Dual tree complex wavelet transform and corresponding failure extreme value using the breakdown judge of Hybrid HVDC route according to judging failure
Type simultaneously carries out corresponding protection act, comprising:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route, and positive and negative polar curve
Road traveling-wave protection quick acting;
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure, and select using failure
Pole judgment basis judges the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode traveling-wave protection is quick
Movement;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting;
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault, and using simultaneously
Pole judgment basis is selected to judge the polarity of failure using failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode row
Wave protects quick acting;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting.
The Hybrid HVDC route traveling-wave protection system 200 based on Dual Tree Complex Wavelet variation of the embodiment of the present invention
With the Hybrid HVDC route traveling-wave protection method that is changed based on Dual Tree Complex Wavelet of another embodiment of the invention
100 is corresponding, and details are not described herein.
The present invention is described by reference to a small amount of embodiment.However, it is known in those skilled in the art, as
Defined by subsidiary Patent right requirement, in addition to the present invention other embodiments disclosed above equally fall in it is of the invention
In range.
Normally, all terms used in the claims are all solved according to them in the common meaning of technical field
It releases, unless in addition clearly being defined wherein.All references " one/described/be somebody's turn to do [device, component etc.] " are all opened ground
At least one example being construed in described device, component etc., unless otherwise expressly specified.Any method disclosed herein
Step need not all be run with disclosed accurate sequence, unless explicitly stated otherwise.
Claims (10)
1. a kind of Hybrid HVDC route traveling-wave protection method based on Dual Tree Complex Wavelet variation, which is characterized in that described
Method includes:
Voltage difference modulus and voltage common mode amount are calculated according to the DC voltage of the positive and negative anodes of acquisition;
The dual tree complex wavelet transform of voltage difference modulus is calculated using dual tree complex wavelet transform, and is sentenced according to high sensitivity starting
Disconnected foundation judges whether protection starts;
When determining protection starting, according to voltage common mode amount, the dual tree complex wavelet transform of voltage difference modulus and corresponding failure
Extreme value judges fault type using the breakdown judge foundation of Hybrid HVDC route and carries out corresponding protection act, wherein
The breakdown judge foundation of the Hybrid HVDC route includes: bipolar error protection judgment basis, monopole metallicity failure guarantor
Shield judgment basis, monopole protect judgment basis and failure to select pole judgment basis through transition Resistance Fault.
2. the method according to claim 1, wherein calculating voltage difference modulus and voltage common mode using following formula
Amount:
F (x)=0.5x (U1-U2),
f1(x)=0.5x (U1+U2),
Wherein, f (x) is voltage difference modulus;f1It (x) is voltage common mode amount;U1And U2The direct current of the positive and negative anodes respectively acquired
Pressure.
3. the method according to claim 1, wherein described calculate voltage differential mode using dual tree complex wavelet transform
The dual tree complex wavelet transform of amount, and judge whether protection starts according to high sensitivity starting judgment basis, comprising:
The dual tree complex wavelet transform W of differential mode amount is calculated using dual numbers complex wavelet transformSF (x), and started according to high sensitivity
Judgment basis judges WSWhether f (x) > Δ 3 meets, if WSF (x) > Δ 3, it is determined that protection starting, and calculate voltage common mode amount
Three cubed integrated value ∫ Ucom 3;Conversely, determining that protection does not start;Wherein, S is scaling function;Δ 3 is third predetermined threshold value, is
Positive value.
4. the method according to claim 1, wherein
The bipolar error protection judgment basis are as follows:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route;
The monopole metallicity error protection judgment basis are as follows:
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure;
The monopole protects judgment basis through transition Resistance Fault are as follows:
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault;
The failure selects pole judgment basis are as follows:
If ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault;
Wherein, f (x) is voltage difference modulus;WSF (x) is the dual tree complex wavelet transform of f (x);S is scaling function, x01For route
The modulus maximum point of dual tree complex wavelet transform when the bipolar failure in end;WSf(x01) antithesis tree when being line end bipolar failure
The modulus maximum of complex wavelet transform, k1For the coefficient of ratio;x02Antithesis tree is multiple small when for line end monopole metallic earthing failure
The modulus maximum point of wave conversion;WSf(x02) be line end monopole failure when dual tree complex wavelet transform modulus maximum;k2For
The coefficient of ratio;x03Modulus maximum point for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;WSf(x03)
Modulus maximum for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;k3For the coefficient of ratio;f1(x) it is
Voltage common mode amount, Δ 1 are the first preset threshold, are positive value;Δ 2 is the second preset threshold, is negative value.
5. according to the method described in claim 4, it is characterized in that, it is described when determine protection starting when, according to voltage common mode amount,
The dual tree complex wavelet transform of voltage difference modulus and corresponding failure extreme value using Hybrid HVDC route breakdown judge according to
It is judged that fault type and carrying out corresponding protection act, comprising:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route, and positive and negative anodes circuit row
Wave protects quick acting;
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure, and select pole to sentence using failure
Disconnected foundation judges the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode traveling-wave protection quick acting;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting;
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as that monopole through transition Resistance Fault, and utilization and utilizes
Failure selects pole judgment basis to judge the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as that cathode failure, cathode traveling wave are protected
Protect quick acting;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting.
6. a kind of Hybrid HVDC route traveling-wave protection system based on Dual Tree Complex Wavelet variation, which is characterized in that described
System includes:
Computing unit, the DC voltage for the positive and negative anodes according to acquisition calculate voltage difference modulus and voltage common mode amount;
Judging unit, for the dual tree complex wavelet transform using dual tree complex wavelet transform calculating voltage difference modulus, and according to
High sensitivity starting judgment basis judges whether protection starts;
Protection location is used for when determining protection starting, according to the dual tree complex wavelet transform of voltage common mode amount, voltage difference modulus
Fault type is judged using the breakdown judge foundation of Hybrid HVDC route with corresponding failure extreme value and is protected accordingly
Shield movement, wherein the breakdown judge foundation of the Hybrid HVDC route includes: bipolar error protection judgment basis, monopole
Metallicity error protection judgment basis, monopole protect judgment basis and failure to select pole judgment basis through transition Resistance Fault.
7. system according to claim 6, which is characterized in that in the computing unit, calculate voltage using following formula
Differential mode amount and voltage common mode amount:
F (x)=0.5x (U1-U2),
f1(x)=0.5x (U1+U2),
Wherein, f (x) is voltage difference modulus;f1It (x) is voltage common mode amount;U1And U2The direct current of the positive and negative anodes respectively acquired
Pressure.
8. system according to claim 6, which is characterized in that in the judging unit, using dual tree complex wavelet transform
The dual tree complex wavelet transform of voltage difference modulus is calculated, and judges whether protection starts according to high sensitivity starting judgment basis,
Include:
The dual tree complex wavelet transform W of differential mode amount is calculated using dual numbers complex wavelet transformSF (x), and started according to high sensitivity
Judgment basis judges WSWhether f (x) > Δ 3 meets, if WSF (x) > Δ 3, it is determined that protection starting, and calculate voltage common mode amount
Three cubed integrated value ∫ Ucom 3;Conversely, determining that protection does not start;Wherein, S is scaling function;Δ 3 is third predetermined threshold value, is
Positive value.
9. system according to claim 6, which is characterized in that
The bipolar error protection judgment basis are as follows:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route;
The monopole metallicity error protection judgment basis are as follows:
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure;
The monopole protects judgment basis through transition Resistance Fault are as follows:
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as monopole through transition Resistance Fault;
The failure selects pole judgment basis are as follows:
If ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault;
Wherein, f (x) is voltage difference modulus;WSF (x) is the dual tree complex wavelet transform of f (x);S is scaling function, x01For route
The modulus maximum point of dual tree complex wavelet transform when the bipolar failure in end;WSf(x01) antithesis tree when being line end bipolar failure
The modulus maximum of complex wavelet transform, k1For the coefficient of ratio;x02Antithesis tree is multiple small when for line end monopole metallic earthing failure
The modulus maximum point of wave conversion;WSf(x02) be line end monopole failure when dual tree complex wavelet transform modulus maximum;k2For
The coefficient of ratio;x03Modulus maximum point for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;WSf(x03)
Modulus maximum for line end monopole through dual tree complex wavelet transform when transition Resistance Fault;k3For the coefficient of ratio;f1(x) it is
Voltage common mode amount, Δ 1 are the first preset threshold, are positive value;Δ 2 is the second preset threshold, is negative value.
10. system according to claim 9, which is characterized in that in the protection location, when determining protection starting, root
Hybrid HVDC route is utilized according to voltage common mode amount, the dual tree complex wavelet transform of voltage difference modulus and corresponding failure extreme value
Breakdown judge according to judging fault type and carry out corresponding protection act, comprising:
If WSF (x) > k1WSf(x01) set up, then it is judged as the bipolar failure of Hybrid HVDC route, and positive and negative anodes circuit row
Wave protects quick acting;
If k2WSf(x02) < WSF (x) < k1WSf(x01) set up, then it is judged as monopole metallicity failure, and select pole to sentence using failure
Disconnected foundation judges the polarity of failure, if ∫ f1 3(x) > Δ 1 is set up, then is judged as cathode failure, cathode traveling-wave protection quick acting;
If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting;
If k3WSf(x03) < WSF (x) < k2WSf(x02) set up, then it is judged as that monopole through transition Resistance Fault, and utilization and utilizes
Failure selects pole judgment basis to judge the polarity of failure, if ∫ f13(x) > Δ 1 is set up, then is judged as that cathode failure, cathode traveling wave are protected
Protect quick acting;If ∫ f1 3(x) < Δ 2 is set up, then is judged as positive electrode fault, positive traveling-wave protection quick acting.
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110535104A (en) * | 2019-07-23 | 2019-12-03 | 中国电力科学研究院有限公司 | A kind of DC line fast protection method and system |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1870378A (en) * | 2006-06-29 | 2006-11-29 | 南京南瑞继保电气有限公司 | Travelling wave identification method of superhigh voltage DC line fault |
US20130015878A1 (en) * | 2011-06-20 | 2013-01-17 | Erlphase Power Technologies Limited | Power system fault zone detection |
CN104065048A (en) * | 2014-07-01 | 2014-09-24 | Abb技术有限公司 | Protection method and protection device of bipolar multi-terminal DC power transmission system |
CN105244861A (en) * | 2015-10-23 | 2016-01-13 | 清华大学 | Transmission line protection method and transmission line protection device |
CN106443329A (en) * | 2016-09-07 | 2017-02-22 | 南京南瑞继保电气有限公司 | System and method for detecting fault of DC grounding electrode line |
CN106443340A (en) * | 2016-09-27 | 2017-02-22 | 华南理工大学 | Time-domain fault location method based on single-circuit electrical quantity double-circuit DC transmission line on the same tower |
CN106526422A (en) * | 2016-11-11 | 2017-03-22 | 清华大学 | Method for processing fault traveling wave of flexible DC transmission line |
CN107666150A (en) * | 2016-07-27 | 2018-02-06 | 全球能源互联网研究院 | DC line fault fast protection method and device in overhead line flexible direct current power network |
CN108054736A (en) * | 2017-11-27 | 2018-05-18 | 山东大学 | A kind of multiterminal flexible direct current power grid DC line protection method based on voltage pole ripple |
-
2018
- 2018-07-09 CN CN201810747106.6A patent/CN109038515B/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1870378A (en) * | 2006-06-29 | 2006-11-29 | 南京南瑞继保电气有限公司 | Travelling wave identification method of superhigh voltage DC line fault |
US20130015878A1 (en) * | 2011-06-20 | 2013-01-17 | Erlphase Power Technologies Limited | Power system fault zone detection |
CN104065048A (en) * | 2014-07-01 | 2014-09-24 | Abb技术有限公司 | Protection method and protection device of bipolar multi-terminal DC power transmission system |
CN105244861A (en) * | 2015-10-23 | 2016-01-13 | 清华大学 | Transmission line protection method and transmission line protection device |
CN107666150A (en) * | 2016-07-27 | 2018-02-06 | 全球能源互联网研究院 | DC line fault fast protection method and device in overhead line flexible direct current power network |
CN106443329A (en) * | 2016-09-07 | 2017-02-22 | 南京南瑞继保电气有限公司 | System and method for detecting fault of DC grounding electrode line |
CN106443340A (en) * | 2016-09-27 | 2017-02-22 | 华南理工大学 | Time-domain fault location method based on single-circuit electrical quantity double-circuit DC transmission line on the same tower |
CN106526422A (en) * | 2016-11-11 | 2017-03-22 | 清华大学 | Method for processing fault traveling wave of flexible DC transmission line |
CN108054736A (en) * | 2017-11-27 | 2018-05-18 | 山东大学 | A kind of multiterminal flexible direct current power grid DC line protection method based on voltage pole ripple |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110535104A (en) * | 2019-07-23 | 2019-12-03 | 中国电力科学研究院有限公司 | A kind of DC line fast protection method and system |
CN110535104B (en) * | 2019-07-23 | 2022-07-01 | 中国电力科学研究院有限公司 | Direct-current line rapid protection method and system |
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